Homogeneous mixtures of polyamides and hydroxyl-containing polyolefines

ABSTRACT

The invention relates to homogeneous injection mouldable compositions which comprise 70 to 99.9 percent by weight of a polyamide and 0.1 to 30 percent by weight of a hydroxylcontaining polyolefine. Saponified copolymers of ethylene and vinyl acetate are suitable for use as hydroxyl-containing polyolefines.

A United I States Patent [191 Bottenhruch et a1.

[ Apr. 10, 1973 [75] Inventors: Ludwig HOMOGENEOUS MIXTURES OFPOLYAMIDES AND HYDROXYL- CONTAINING POLYOLEFINES Bottenbruch; DietrichMichael; Werner Nielinger, all of Krefeld Bockum, Germany [7 3]Assignee: Farbeniabriken Bayer AG, Krefeld- Bockum, Germany [22] Filed:Feb. 11, 1972 [21] Appl. No.: 225,619

Related US. Application Data [63] Continuation-in-part of Ser. No.28,562, April 14,

1970, abandoned.

[52] US. Cl ..260/857 L, 260/78 R [51] Int. Cl. ..C08g 41/04 [58] Fieldof Search ..260/ 857 L [56] References Cited UNITED STATES PATENTS 2,473,403 6/ 1949 Woodward .260/ 857 Primary Examiner-Paul LiebermanAttorney-Allan R. Plumley et al.

[57] ABSTRACT The invention relates to homogeneous injection mouldablecompositions which comprise 70 to 99.9 percent by weight of a polyamideand 0.1 to 30 percent by weight of a hydroxyl-containing polyolefine.Saponified copolymers of ethylene and vinyl acetate are suitable for useas hydroxyl-containing polyolefines.

5 Claims, No Drawings HOMOGENEOUS MIXTURES OF POLYAMIDES ANDHYDROXYL-CONTAINING POLYOLEFINES This is a continuation-in-part ofcopending U.S. patent application Ser. No. 28,562, filed Apr. 14, 1970now abandoned.

The present invention relates to new homogeneous suitable for injectionmoulding mixtures of polyamides and hydroxyl-containing polyolefines andto a process for their preparation.

Polyamides such as polycaprolactam are distinguished by their hightensile strength, toughness and rigidity. However, their reducedflexibility at low temperatures is sometimes a disadvantage.

Attempts have been made to obtain polyamides which are more flexible atlow temperatures by mixing polyamides with polymers which have a verylow freezing point. The properties of such mixtures, for example ofmixtures of polyamide and polyethylene, are not very satisfactorybecause the polyamides are incompatible with other polymers and thesepolymers are therefore difficult to disperse in the polyamide.

The dispersibility of polyoleflnes in polyamides can be improved byadding dispersing agents when preparing the mixtures or by graftingpolyolefine and polyamide.

It is also known that products which have an improved notched impactstrength at low temperatures are obtained when polyamides containpolyamide side chains which are grafted on carboxyl-containingcopolymers of ethylene.

It is an object of this invention to provide polyamides with an improvedflexibility at low temperatures.

This object is accomplished by compositions of polyamides andhydroxyl-containing olefine copolymers which are characterized byimproved flexibility at low temperatures in the same way as lesscrystalline types of polyamides. At the same time, they resemble themore crystalline types in their improved properties for working up, suchas the ease with which they can be removed from moulds.

More particularly, the present invention relates to a homogeneousmixture of polyamides and polyolefines suitable for injection mouldingwhich comprises a. 70 to 99.9 percent by weight of a polyamide and b.0.1 to 30 percent by weight of a hydroxyl-containing polyolefine whichconsists of 60 to 90 percent by weight of recurrent units of the generalformula r 1 TlTiJ and 10 to 40 percent by weight of recurrent units ofthe formula:

fji Li i1 wherein R R R and R which may be the same or different,represent a hydrogen atom, a lower alkyl group or a halogen atom,

the polyolefine having a molecular weight in the region of 10 to 10 andthe homogeneous, suitable for injection moulding mixture having arelative solution viscosity of at least 2.0.

The viscosity is measured on a solution of l g of the mixture in 100 mlof m-cresol at 25 C in an Ubbelohde viscosimeter.

Saponified copolymers of ethylene and vinyl acetate are particularlysuitable for use as the hydroxyl-containing polyoleflnes. Thepolyoleflnesshould contain 10 to 40 percent by weight of units of theformula For the purpose of this invention, polyamides are understood tomean high molecular weight polyamides which can be derived from amonoaminocarboxylic acid having at least six carbon atoms or from a saltof a dicarboxylic acid and a diamine. They are prepared by hydrolyticpolymerization. By way of explanation these polyamides consist of linearunbranched polymer chains containing no additional functional groups.The compound used is preferably polycaprolactam.

to 99.9 percent by weight of the mixture should consist of polyamide.

The modified polyamides may be prepared by hydrolytic polymerization ofthe aminocarboxylic acids or of their derivatives or of the salts ofdicarboxylic acids and diamines in the presence of the copolymers. Thecopolymers may be introduced into the reaction vessel together with thepolyamide-forming starting materials but is has been found to beadvantageous to add the copolymers subsequently to the slightly viscousEXAMPLE 1 e-Caprolactam is polymerized with 9 percent by weight ofe-aminocaproic acid and 0.09 percent by weight of glacial acetic acidfor 1 hour at 200 C with stirring under a nitrogen atmosphere. Thetemperature is then raised to 270 C. One hour after this temperature hasbeen reached, 0.1, 1.0 and 5.0 percent by weight, respectively, of asaponified copolymer of ethylene and vinyl acetate having a molecularweight of 20,000 and an OH number of 255 are introduced into theslightly viscous melt. After a further 6 hours, the melt is spun as abristle into a water bath and chopped up. The chopped material isextracted four times with water at C, each time for 3 hours, and is thendried in a vacuum drying cupboard at C for 24 hours. The granulate isshaped by injection moulding and the mechanical properties of themoulded products are then determined. The dataare summarized in thetable below. Number 4 is a comparison product made of purepolycaprolactam.

Serial Polyolefine Relative Flexural Elastic modulus No. content insolution stress at obtained from by weight viscosity at given thebending test 1 rel deflection (lg/100ml kg wt/cm kg wt/cm m-cresol atroom at at room at at 25 C) temp. -20C temp 20C 1 0.1 3.58 1160 i'szoEmir 275150 EXAMPLE 2 9.5 kg of polycaprolactam having a relativesolution viscosity of 3.1 determined on a 1 percent solution in m-cresolat 25 C are intensively mixed with 0.5 kg of a saponified copolymer ofethylene and vinyl acetate having a molecular weight of 20,000 and an OHnumber of 255.

This mixture is extruded, chopped up and shaped by injection moulding.The products are distinguished by being easily removed from the mouldand by their im- FR Bl Tifil and 10 to 40 percent by weight of recurrentunits of the formula wherein R R and R which may be the same ordifferent, represent a hydrogen atom, a lower alkyl group or a halogenatom, the polyolefine having a molecular weight in the region of 10 to10 and the homogeneous, suitable for injection moulding mixture having arelative solution viscosity of at least 2.0.

2. The composition as claimed ll'l claim 1, m which the polyamide ispolycaprolactam and the hydroxylcontaining polyolefine is a saponifiedcopolymer of ethylene and vinyl acetate.

3. The homogeneous injection moldable composition as claimed in claim 1,which consists of a homogeneous melt blend of said polyamide and saidpolyolefine.

4. The homogeneous melt blend composition as claimed in claim 3 obtainedby adding said hydroxylcontaining polyolefine to a melt of a preformedpolyamide.

5. The homogeneous melt blend composition as,

claimed in claim 3, obtained by adding said hydroxylcontainingpolyolefine to polyamide-forming starting materials.

' UNITED S'IA'EEH' I'A'lllN'l UFFHIB. (Ilflli'llFHIATE HF CUREHQQ'EEUNPatent No. 5 Dated April 10, 1973 Inventor) Ludwig Bottenbruch; at l Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

[73} Assignee: I "Krefeld-Bockum, Germany" should read -Leverkusen,Germany Column 3, line 33, "polyamdie" should read --polyamide'--i-.

Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

MCCOY GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents

2. The composition as claimed in claim 1, in which the polyamide ispolycaprolactam and the hydroxyl-containing polyolefine is a saponifiedcopolymer of ethylene and vinyl acetate.
 3. The homogeneous injectionmoldable composition as claimed in claim 1, which consists of ahomogeneous melt blend of said polyamide and said polyolefine.
 4. Thehomogeneous melt blend composition as claimed in claim 3, obtained byadding said hydroxyl-containing polyolefine to a melt of a preformedpolyamide.
 5. The homogeneous melt blend composition as claimed in claim3, obtained by adding said hydroxyl-containing polyolefine topolyamide-forming starting materials.